Stretching- and cutting-device on machines for pulling out threads



K. MISCHKE Nov. 6, 1934.

1,979,39 STRII'ICJIIING AI iD CUTTING DEVICE ON MACHINES FOR PULLING OUT THREADS Filed Sept. 4, 1928 Patented Nov. 6, 1934 UNITED STATES STRETCHING- AND CUTTING-DEVICE ON MACHINES FOR PULLING OUT THREADS Karl Mischke, Zurich, Switzerland, assignor to Diirkopp-Werke A.-G., Bielefeld, Germany Application September 4, 1928, Serial No. 303,930

2 Claims.

This invention relates to a stretching and cutting-device on machines for pulling out threads, in which a counter-knife is embedded in the throat plate so that it is lifted only at the cutting moment to stretch the cloth or fabric by'the cutting knife, presser feet being further arranged connected to the presser foot rod for obtaining the absolutely uniform guiding, pressing and stretching of the material necessary for the cutting off, said presser feet diverging from the front to the rear.

An embodiment of the invention is illustrated, by way of example, in the accompanying drawing, in which Fig. 1 is a front elevation of the machine.

Fig. 2 is a top plan view of the stitch plate for the machine shown in Fig. 1. i

Fig. 3 shows in top plan View the driving element for the cloth presser wheels.

Fig. 4 shows in top plan view on larger scale the knife and counter knife according to Fig. 1. Fig. 5 is a longitudinal section through the throat plate with the knife and the counter knife.

According to the invention a transporting beam 33 operates in a similar manner to the beam of an ordinary sewing machine performing a rising, falling and reciprocating movement. For this purpose it is mounted at one end on the transporting shaft 32 and is slidably guided at the other end in a counter bearing 34. A knife support 35 is arranged on this transporting beam having a cut slot 38 in which a U-shaped knife 36 is fixed by means of a screw 37. The knife support is arranged at an incline to the throat plate 40 so that the cutting edge of the knife cooperates like shears with a counter knife 39 mounted on the throat plate 40, a special guide slot 41 is arranged in the lower portion of the throat plate 40 for the counter knife 39. The cutting edge of the knife 36 lies in cutting position at such an angle to the counter knife 39 that it lifts this latter during the cutting operation. This knife 36 consists of a smooth obtuse angled piece which is easily interchangeable.

On a hollow presser foot rod 15 wheels 42 are arranged so that they can rotate and so that they are standing at an angle the one to the other. These wheels 42 have teeth 43 with which a worm Wheel 44 meshes positively. This worm wheel 44 is rotated from the machine through a shaft 45 extending through the shaft 15 and driven by transmission means 46.

A depression 47 is provided in the throat plate 40 in which engage the wheels 42 which have tires of elastic material, for instance rubber, so that the material must be strongly stretched and guided by the wheels mutually inclined at an angle. A blade spring 48 serves throat plate.

as cloth presser and for assisting the stretching.

The depth of the depression 47 is equal to the distance which the wheels 42 descend. The object of this depression is in cooperation with the inclined wheels 42 to strongly stretch the cloth to be worked. This is effected in that, by the wheels being set at an angle, the cloth is pulled apart from the front towards the rear, and the cloth on being pulled by the wheels is drawn tightly over the front edge of the depression.

The counter knife 39 is situated under this stretched material. When therefore this counter knife 39 is raised under the action of the knife 36, the stretched material as it cannot yield because it is held by the guide wheels 42, 42', will be stretched to a still greater extent especially at the cutting point.

As the counter knife 39 is flush with the throat plate and is only raised under the influence of the knife 36, the knife 36 cannot strike against the edge of the counter knife 39.

For ascertaining if the material is fed parallel to the run of the threads, one or several inclined pointed needles 49 are mounted in the The material is conducted over the needles which slightly press upward the threads of the fabric so that, according to the number of needles, one or several raised lines are produced which indicate even the slightest deflection in the thread course from the straight guiding in front of the pulling-out needle.

I claim:

1. A stretching and cutting device on machines for pulling out threads, comprising in combination with the throat plate, a counter knife embedded in said throat plate, a cutting knife arranged under and at an angle to said throat plate adapted to lift said counter knife at the moment of cutting and to stretch the cloth, a presser foot rod, and presser feet on said presser foot rod diverging from the front towards the rear adapted to uniformly guide, press and stretch the cloth to facilitate the cutting.

2. A'device as specified in claim 1 in which the presser feet are in the form of positively driven stretching and transporting wheels which are arranged at an angle the one to the other and fitted with rubber tires and the throat plate has a depression corresponding to the radius of said wheels, adapted in conjunction with said Wheels to tightly stretch the cloth.

KARL MISCHKE. 

